Amicus Curiae Brief of
Mark Cuban et al.

I. No one is seriously burdened by reasonable limits on superPAC contributions.

Reasonable limits on superPAC contributions only minimally burden the speech rights of Americans like amici. In this context, the rationales for treating candidate contributions as lower-value speech that the Supreme Court articulated in Buckley v. Valeo apply with equal force: "(1) a super PAC contribution does not convey the underlying basis for the contributor's support, (2) its transformation into debate requires speech by someone other than the contributor, and (3) limiting it does not prevent the contribution from serving as a symbolic expression of support or restrict the contributor's ability to discuss candidates and issues." Thus, "Buckley and its progeny require treating contribution limits as 'marginal speech restrictions subject to relatively complaisant review under the First Amendment, because contributions lie closer to the edges than to the core of political expression.'"

For at least three reasons, superPAC contributions are even lower-value speech than the candidate contributions at issue in Buckley. First, an increasing number of superPAC contributions are essentially anonymous: donations are often funneled through shell entities, or "dark money" organizations. These associations—often bearing vague, apolitical names—help conceal the identities of individual donors. These donations communicate essentially no useful information to voters about the message or ideology the contribution expresses.

Second, some superPACs engage in "bet-hedging," contributing similar amounts to opposing candidates in a single election. These donations don't express support for either candidate, but instead aim to curry favor with the eventual winner. For example, in a recent Georgia election, two large "dark money" nonprofits funded superPACs that "simultaneously supported one state official who resisted [President] Trump's effort to overturn the 2020 election while boosting the challenger to another official Trump unsuccessfully sought to pressure." Bet-hedging is also common in Presidential races. As one pharmaceutical industry observer explained before the 2024 election,

Third, superPAC contributions are no more revealing in the aggregate than they are individually. Twelve individuals (six generally supporting Democrats, six generally supporting Republicans) alone contributed an estimated $1 out of every $13 in politics between 2009 and 2020. In the 2020 cycle, 91% of contributions to superPACs affiliated with Congressional leadership on both sides of the aisle came from donors who gave $100,000 or more; 74% came from donors who gave $1 million or more. These and other megadonors, collectively, distribute their spending almost evenly across both major parties. The result is a noisier campaign season, but not one that gives voters useful information about each candidate's base of support.

II. Unlimited superPAC contributions create a serious risk of actual quid pro quo corruption and its appearance.

The First Amendment authorizes campaign finance regulations to combat quid pro quo corruption—where "large contributions are given to secure a political quid pro quo." "The hallmark of [quid pro quo] corruption is … dollars for political favors." Today, direct campaign contributions, which are subject to contribution limits, are no longer the principal channel for this kind of corruption. "Political money, like water, must go somewhere." Donors may not be able to make unlimited contributions to individual candidates, but they can and do choose to funnel money into superPACs.

Courts have assumed Buckley's observation that independent expenditures do not, as a matter of law, give rise to corruption also applies to contributions to independent expenditure entities like superPACs. But recent experience belies this tautology. Numerous federal prosecutions have involved the exchange of political favors for contributions to aligned superPACs. These include an alleged bribery scheme involving Senator Bob Menendez, who was accused of "using his Senate office to influence contractual and Medicare billing disputes to [the donor's] benefit" in exchange for donations including "$600,000 in super PAC contributions"; another scheme involving a former North Carolina Insurance Commissioner, where an insurance executive allegedly "fund[ed] outside groups that would spend money to benefit [the Commissioner's] re-election" "in exchange for the removal of an insurance commission official who oversaw [the executive's] company"; an alleged RICO scheme where an electric utility allegedly "fund[ed] a super PAC … that paid for advertisements benefiting" the eventual Speaker of the Ohio House of Representatives, who then helped "pass and uphold a billion-dollar nuclear plant bailout" that benefited the utility; and an alleged bribery scheme involving the Governor of Puerto Rico, who was accused of agreeing to replace an oversight official in exchange for an executive's promise to support her politically by "creat[ing] a super PAC supporting her." It does not follow, legally or logically, that contributions to superPACs cannot give rise to quid pro quo corruption.

Quid pro quo corruption can take the form of clientelism, whereby "political support (votes, attendance at rallies, money) is exchanged for privileged access to public goods." Individuals and corporations can exploit the system to help them achieve private gains through public means. In prominent cases across the country, individuals and corporations have used superPAC contributions to support elected officials with the power to steer public contracts their way. Executives have donated extensively to superPACs supporting state officials who "directed lucrative state pension investments to their firms," circumventing rules that limit direct contributions to campaigns. A military technology company allegedly used a superPAC to launder donations to support a Senator who had "strongly advocated for" the company to receive an $8 million contract from the U.S. Navy. Researchers have found evidence of "politicians not only rewarding supporters but also punishing opponents" by granting (or withholding) exemptions to industry-wide tariffs, suggesting "quid pro quo arrangements between politicians and firms."

Another example is the common practice of appointing wealthy donors to prominent public offices. In the last administration, the President's ambassadorial nominees and their spouses had donated over $22 million to party-affiliated committees in the decade prior to their nomination and "millions more to super PACs that can raise and spend unlimited sums to help Senators get elected"—Senators who then vote on whether to confirm the President's ambassadorial appointments. Some appointees lacked substantive foreign policy experience or didn't know the native language of the country they served in. The current Secretary of Education had no teaching experience prior to her appointment, but she had donated tens of millions of dollars to various superPACs supporting the President who appointed her.

Unlimited superPAC contributions also undermine campaign finance regulations aimed at deterring corruption. Take, for example, the apparent use of superPAC contributions to skirt New York City's rule that individuals doing business in the city may not give more than $400 to a citywide candidate. In the 2025 mayoral campaign, one major real estate developer violated this rule, initially contributing $2,100 directly to one candidate's campaign. The campaign quickly refunded the developer—but then one day later the developer donated $250,000 to a superPAC supporting the candidate. At the federal level, federal contractors have evaded direct contribution bans by donating to superPACs supporting federal candidates. While it's unclear whether these examples yielded quid pro quos, they do illustrate ways superPAC contributions can enable "corporations to buy taxpayer-funded contracts with political contributions, and, vice versa, for politicians to reward political contributors with lucrative contracts."

These kinds of exchanges, at minimum, feed "the appearance of corruption stemming from public awareness of the opportunities for abuse inherent in a regime of large individual financial contributions." This is especially true in small states like Maine, where the cost of legislative and statewide races is a fraction of the cost in larger states. Maine is one of a handful of states that helps fund state elections through "clean election" public funding, but relatively modest outside contributions can swamp the public funding system and create dynamics that give rise to corruption. Indeed, Maine has already seen an explosion in superPAC spending, especially in federal elections. With campaign spending (and spending by dark money groups) increasing every election cycle, it is unsurprising that many Americans now perceive corruption as a defining feature of American politics. Across partisan lines, majorities believe there is too much money in politics, that elected officials are "bought off," and that campaign donors are effectively paying bribes. The absence of limits on superPAC contributions feeds this widespread and warranted belief.

III. Allowing states to enforce reasonable limits on superPAC contributions will make government more responsive to ordinary voters.

As the Supreme Court stated in a major campaign finance opinion, the concept of responsiveness is "at the heart of the democratic process." When individuals vote for or contribute to a candidate who shares their beliefs, they reasonably expect that the candidate will be responsive to their concerns. Yet our current system ensures that candidates are largely unresponsive to their voters. Instead, candidates often focus their time and energy on issues that the general public does not care about—and take positions their constituents do not generally support—to align with the demands of donors. These dynamics hold true whether donations come in the form of direct campaign contributions or donations to aligned superPACs.

Contributions shape how elected officials spend their time and what policies they enact. Members of Congress are three times more likely to meet with donors than with constituents. Legislators who receive a larger share of donations from outside their districts—donations that national superPACs can help funnel into state and local races—vote in ways that are less ideologically aligned with their constituents' preferences. On the whole, economic elites and organized business interests exert substantial influence on U.S. policy outcomes, while average citizens and mass-based interest groups exert little or none.

A system in which elected officials are unresponsive to the needs of voters undermines democratic accountability—and, in the long run, economic vibrancy. Wealth inequality is not inherently suspect. Across the world, strong democracies persist despite significant concentrations of wealth. However, where wealth is dependent on "political privilege"—and wealth accumulation is contingent on staying in the government's favor—the free market suffers, ultimately hindering investment and efficient production. Amici have worked hard to amass their fortunes and benefitted from the rules-based legal system that undergirds America's democracy and world-leading economy. The current campaign finance system jeopardizes both.